DTC P0115 Engine Coolant Temperature Circuit
DTC P0117 Engine Coolant Temperature Circuit Low Input
DTC P0118 Engine Coolant Temperature Circuit High Input
DESCRIPTION
A thermistor is built into the Engine Coolant Temperature (ECT) sensor, of which the resistance value varies according to the ECT.
The structure of the sensor and its connection to the ECM are the same as those of the Intake Air Temperature (IAT) sensor.
HINT: When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the ECT is estimated to be 80C (176F) by the ECM. Fail-safe mode continues until a pass condition is detected.
DTC No. |
Proceed to |
DTC Detection Condition |
Trouble Area |
P0115 | Step 1 | Open or short in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic) |
|
P0117 | Step 4 | Short in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic) |
|
P0118 | Step 2 | Open in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic) |
|
HINT: When any of these DTCs are set, check the ECT by selecting the following menu items on the intelligent tester: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
MONITOR DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is used to monitor the ECT. The ECT sensor has a thermistor with a resistance that varies according to the temperature of the engine coolant. When the coolant temperature becomes low, the resistance in the thermistor increases. When the temperature becomes high, the resistance drops.
These variations in resistance are reflected in the voltage output from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the ECT. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the ECT sensor and sets a DTC.
Example: If the sensor voltage output is -40C (-40F) for 0.5 seconds or more, the ECM determines that there is an open in the ECT sensor circuit, and sets DTC P0118. Conversely, if the voltage output is more than 140C (284F) for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0117.
If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P0115:
P0117:
P0118
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
1 READ VALUE OF INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE)
Standard: Between 80C and 97C (176F and 207F) with warm engine.
HINT:
2 READ VALUE OF INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)
Standard: 140C (284F) or higher
3 CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)
Standard resistance
REPLACE ECM
4 READ VALUE OF INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)
Standard: -40C (-40F)
5 CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)
Standard resistance
REPLACE ECM
Removal
1. REMOVE REAR WHEEL
2. REMOVE SKID CONTROL SENSOR WIRE (for 2WD)
(a) Disconnect the skid control sensor connector.
(b) Remove the bolt and disconnect the bracket from
the rear axle beam assembly.
HINT:
Separate the RH side by the same procedures as
the LH side.
3. SEPARATE SPEED SENSO ...
Aluminum wheel precautions
Use only Toyota wheel nuts and wrenches designed for use with
your aluminum wheels.
When rotating, repairing or changing your tires, check that the
wheel nuts are still tight after driving 1000 miles (1600 km).
Be careful not to damage the aluminum wheels when using tire
chains.
Use o ...
Rear Clearance Sonar Sensor LH Circuit
DESCRIPTION
An ultrasonic sensor consists of a sensor portion that transmits and receives
ultrasonic waves and a preamplifier
that amplifies them. The ultrasonic sensor outputs the ultrasonic waves and
sends the received
signals to the clearance warning ECU.
WIRING DIAGRAM
INSPECTION PR ...